I'm having issues trying to burn CDs and DVDs. (Frankly, I only care about burning CDs at this point.)

This is a work machine and I have a script creating an ISO of key files every Sunday. I come in Monday morning and use K3B to burn the ISO to CD (ISO usually ~300-400MiB.) I was last successful in burning a CD on Feb 5, which was my last attempt. (I was out for the following two weeks and forgot last week.) Monday afternoon I tried but no luck. Nothing had changed on my system since before Feb 5. I tried upgrading cdrecord, cdrdao and dvd+rw-tools and it didn't work. I upgraded my kernel from 2.6.18 to 2.6.19 and that, too, didn't work.

The system will mount burned DVDs and recognize blank DVDs (but not burn them) however, it will not recognize burned CD-Rs or blank CD-Rs at all.

Any ideas where to start looking for clues? Searching Google and the forums comes up with nothing that was useful (most likely my Google-fu is bad.) I'd provide more technical details, but I have no idea what would be useful. Tell me what would help and I'll provide it.

Hadn't had a chance to test with commercial CDs until just now. The disks mount and are readable. (Can't test with any audio CDs, either burned or commercial, as I have none available at this time.)

UPDATE: I tried a burned CD from a conference I attended (burned by the event organizers) that failed to mount as well. Also, if I remember correctly, mounting burned CDs has always been flaky, though burning them was never an issue. Also, I tried mounting a couple of burned CDs as root with no success.